This invention relates to a circuit breaker, and more particularly, to a pivoting arcing contact assembly associated with the main current carrying contacts of the circuit breaker.
Under certain conditions, which are frequently present when the current carrying contacts of a circuit breaker are opened, an arc is generated between the contacts. Depending on the intensity and duration of the arc, the contact material, which in many cases is a precious metal, experiences varying degrees of deterioration and/or separation of the contact material from the contact carrying arms. For example, the contact surfaces can be eroded such that the resistance of the interfaces between contacts increases causing contact heating and further deterioration of the contacts.
To reduce the duration of arcing at the current carrying contacts, it is important to move the arcs from the contacts. This can be done by causing arcs generated at the contacts to commutate to a higher resistance less expensive material. Arc horns or arcing contacts can be used to perform this function. For example, U.S. Pat. No. 4,713,504 discloses an arcing contact hingedly mounted for reducing arcing between separating contacts.
Subsequent to moving arcs from between current carrying contacts to arcing contacts, it is important to extinguish the arcs and/or move the arcs into an arc chute. Accordingly, it would be advantageous to effectively commutate all of the arcs generated at the current carrying contacts in a way which consolidates all of the arcs into a single arc which can be extinguished and/or moved into an arc chute.